Method and device for controlling power amplification

ABSTRACT

A method and network equipment for controlling power amplification are disclosed. The method for controlling power amplification includes outputting a voltage signal according to the state of an NE. The voltage signal is applied to a grid electrode or a base electrode of at least one power amplifier transistor in a power amplifier.

This application is a continuation of U.S. patent application Ser. No.12/684,592, filed on Jan. 8, 2010, which is a continuation ofInternational Application No. PCT/CN2008/071966, filed on Aug. 13, 2008.The International Application claims priority to Chinese PatentApplication No. 200710076519.8, filed on Aug. 17, 2007. All of theseapplications are hereby incorporated by reference in their entireties

TECHNICAL FIELD

The present invention relates to the field of communications, and moreparticularly to a method and a device for controlling poweramplification.

BACKGROUND

A radio frequency (RF) power amplifier is a key component of a networkequipment (NE) in a radio communication system. The RF power amplifieris substantially an energy converter, which converts Direct Current (DC)energy of a power source into RF energy for transmission through anantenna. A ratio of the RF power to the DC power provided by the powersource is referred to as the efficiency η of the power amplifier, andthe efficiency is an important factor of the power amplifier. Taking thepower amplifier in a base station for example, the efficiency isdirectly associated with factors such as the power source, heatdissipation, size, fans, and noises of the base station system. A highefficiency of the power amplifier improves the reliability of the basestation system and reduces the cost of the base station equipment. For atelecommunication operator, a high efficiency of the power amplifier caneffectively reduce the cost of system operation and subsequentmaintenance.

The efficiency η of a power amplifier is calculated according to thefollowing formulae:η=(Power_(—) rf/power_(—) dc)×100%  [1]where Power₁₃ rf is an RF power, and ^(Power) ₁₃dc is a DC power; andPower_(—) dc=V _(dd) ×I _(d)  [2]where V_(dd) is a voltage provided by a DC power source, and I_(d) is acurrent provided by the DC power source.

In the whole power conversion process, a part of the DC energy isinevitably converted into heat, which will be wasted. Therefore, theactual efficiency of the power amplifier is always lower than 100%.

In a current base station power amplifier, to consider the efficiencyand linearity indexes comprehensively, a static working point of thepower amplifier is normally set to Class A or Class AB, that is, astatic working current of the power amplifier I_(dq)>0A. Taking alaterally diffused metal oxide semiconductor (LDMOS) for example, theLDMOS is a power amplifier transistor widely applied at present. If avoltage bias of a power amplifier using the power amplifier transistoris in Class AB, and the power amplifier is in a saturated output state,the efficiency is the highest. However, with the decrease of the outputpower, the efficiency will be reduced gradually. That is, the ratio ofthe heat converted from the DC energy provided by the power source willrise with the decrease of the efficiency of the power amplifier.

When the power amplifier does not output any RF power, the dissipated DCpower is as follows:Power_(—) dc=V _(dd) ×I _(dq)  [3]

For the base station system, the state in which the power amplifier doesnot output any RF power appears frequently (for example, when nosubscriber accesses the system). According to the above analysis, atthis time, for a common Class A or Class AB amplifier, the static poweris wasted, and the overall efficiency of the power amplifier is lowered.

To improve the overall efficiency of the power amplifier, the followingsolution is adopted in the prior art. When the power amplifier is in astate with no RF power output, a voltage of a drain electrode of thepower amplifier transistor in the power amplifier is adjusted to 0V. Itis known from Formula [3] that, at this time, Power_dc=0 W i.e. thedissipated DC power is 0 W.

Though the overall efficiency of the power amplifier is increased tosome extent by using the above method, the inventors found the followingproblems from the solution.

First, the response time is long, the solution is applicable to fewscenarios only, and the improvement to the efficiency of the poweramplifier is limited.

Normally, the drain electrode of the power amplifier transistor operatesin the state of high voltage (for example, 28 V) and large current (forexample, 10 A), so the power supply unit thereof must be a power sourcecapable of providing a high power. Limited by factors such as thecharging and discharging of high-capacitance capacitors and thesoft-start mechanism to ensure security, the time for establishing ordisabling the output voltage of such a power source is often severalseconds or even several tens of seconds.

However, in normal situations, time periods required by services of thebase station system are much shorter than one second. For example, in aGlobal System for Mobile Communications (GSM), the timeslot period ofeach user is only 577 μs. Subscribers may access (the power amplifierneeds to switch on) or not access (the power amplifier needs to switchoff) the GSM system in a timeslot period, while the solution ofcontrolling the voltage of a drain electrode cannot track such a fastchange. To ensure normal communications, the voltage on the drain portof the power amplifier transistor must remain at the normal operatingvoltage without changes for a long time, and thus a part of the staticpower will be dissipated

In view of the above, the solution of controlling the voltage of a drainelectrode is applicable to very few scenarios in practice. Normally,this solution is adopted only when no subscriber accesses the system fora long time at night. Therefore, the improvement to the efficiency ofthe power amplifier is unobvious, and the power-saving effect islimited.

In addition, the control circuit is complicated with a high cost and lowreliability.

The solution of controlling the voltage of a drain electrode deals withsignals with a high voltage and large current, so many high-powerelements are needed. Therefore, the circuit implementation iscomplicated, the cost is high, and the reliability is low, which mayeasily cause potential quality problems.

SUMMARY OF THE INVENTION

Accordingly, the embodiments of present invention provide a method and adevice for controlling power amplification, a base station, and aterminal, so as to improve the efficiency of a power amplifier byreducing static power dissipation in a time period without output power.

In an embodiment of the present invention, a method for controllingpower amplification is provided. The method includes the followingsteps.

Outputting a voltage signal according to the state of an NE. Applyingthe voltage signal to a grid electrode or a base electrode of at leastone power amplifier transistor in a power amplifier.

In an embodiment of the present invention, a transmitter is provided.The transmitter includes a main control unit, a voltage control unit,and a power amplifier unit.

The main control unit is adapted to obtain the state of an NE where thetransmitter is located, and send a voltage control signal according tothe state.

The voltage control unit is adapted to output a voltage signal accordingto the voltage control signal received from the main control unit.

The power amplifier unit is adapted to switch on or switch off accordingto the voltage signal applied to a grid electrode or a base electrode ofat least one power amplifier transistor therein by the voltage controlunit.

In an embodiment of the present invention, a base station is provided.The base station includes a main control unit, a voltage control unit,and a power amplifier unit.

The main control unit is adapted to obtain the state of the basestation, and send a voltage control signal according to the state.

The voltage control unit is adapted to output a voltage signal accordingto the voltage control signal received from the main control unit.

The power amplifier unit is adapted to switch on or switch off accordingto the voltage signal applied to a grid electrode or a base electrode ofat least one power amplifier transistor in the power amplifier unit.

In an embodiment of the present invention, a terminal is provided. Theterminal includes a main control unit, a voltage control unit, and apower amplifier unit.

The main control unit is adapted to obtain the state of the terminal,and send a voltage control signal according to the state.

The voltage control unit is adapted to output a voltage signal accordingto the voltage control signal received from the main control unit.

The power amplifier unit is adapted to switch on or switch off accordingto the voltage signal applied to a grid electrode or a base electrode ofat least one power amplifier transistor therein by the voltage controlunit.

In an embodiment of the present invention, a device for controllingpower amplification is provided. The device includes a main control unitand a voltage control unit.

The main control unit is adapted to obtain the state of equipment, andsend a voltage control signal according to the state.

The voltage control unit is adapted to output a voltage signal to a gridelectrode or a base electrode of at least one power amplifier transistorin a power amplifier unit according to the voltage control signal.

Compared with the prior art, the embodiments of the present inventionachieve the following beneficial effects.

The response time is short, the solution is applicable to morescenarios, and the power amplification efficiency is improved to themaximum extent. The grid electrode of the power amplifier transistornormally operates in the state of low voltage (for example, 3 V) andsmall current (for example, 5 mA), the circuit does not have capacitorswith high capacitance, and the charging/discharging time is at μs levelor even lower. Therefore, the power amplifier transistor can switch onor switch off at the same speed, which is advantageous to a fastresponse to the control signal. Through the control over the gridelectrode or the base electrode of the power amplifier transistor,static power dissipation at a timeslot level is reduced, so as to avoidenergy dissipation to the maximum extent.

The control circuit is simple, the cost is low, and the reliability ishigh. The voltage control unit processes low-voltage and small-currentsignals. The circuit implementation is simple, the cost is low, and thereliability is high.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawing, in which:

FIG. 1 is a flow chart of a method for controlling power amplificationaccording to a first embodiment of the present invention;

FIG. 2 is a schematic view of the relationship between RF power outputof a power amplifier and timeslots according to the first embodiment ofthe present invention;

FIG. 3 is a schematic view of the relationship between power dissipationof a conventional Class AB power amplifier in the prior art andtimeslots;

FIG. 4 is a schematic view of the relationship between power dissipationof the power amplifier and timeslots according to the first embodimentof the present invention;

FIG. 5 is a schematic view of a system for controlling poweramplification according to a second embodiment of the present invention,in which a voltage control unit is connected to a grid of a poweramplifier transistor;

FIG. 6 is a schematic view of a main control unit according to thesecond embodiment of the present invention;

FIG. 7 is a schematic view of the system for controlling poweramplification according to the second embodiment of the presentinvention, in which the voltage control unit is connected to grids oftwo power amplifier transistors;

FIG. 8 is a schematic view of a system for controlling poweramplification according to a third embodiment of the present invention,in which a voltage control unit is integrated in a main control unit;

FIG. 9 is a schematic view of a system for controlling poweramplification according to a fourth embodiment of the present invention,in which a voltage control unit is integrated in a power amplifier;

FIG. 10 is a schematic view of a system for controlling poweramplification according to a fifth embodiment of the present invention,in which power amplifiers are operated independently or connected inparallel in operation; and

FIG. 11 is a schematic view of a system for controlling poweramplification according to a sixth embodiment of the present invention,in which power amplifiers are connected in series in operation.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the embodiments of the present invention, a voltage signal is outputto a grid electrode or a base electrode of a power amplifier transistoraccording to the state of an NE, and the power amplifier transistor canswitch on or switch off according to the state of the NE under thecontrol of the voltage signal, so as to improve the efficiency of apower amplifier.

The technical solutions of the present invention are described in detailbelow in the embodiments with reference to some accompanying drawings.

A method for controlling power amplification is provided in a firstembodiment of the present invention. Referring to FIG. 1, the methodincludes the following steps.

Step S101, outputting a voltage signal according to the state of an NE.

In this step, information related to the NE is obtained firstly. Theinformation includes signaling or service information or externalcontrol signal or internal clock signal of the NE, and the state of theNE can be determined according to one or multiple combinations of theinformation. The NE may be in an Idle or a Busy state. The Idle stateindicates that the NE is not required to output an RF signal, forexample, the NE is not accessed by any subscriber or in an idletimeslot, or receives a control signal for enabling the power amplifierto switch off. The Busy state indicates that the NE is required tooutput an RF signal, for example, the NE is accessed by subscribers, ina non-idle timeslot, or receives a control signal for enabling the poweramplifier to switch on. Taking a base station for example, when aterminal accesses the base station, if a channel type assigned in thesignaling is a main broadcast control channel (BCCH) or a packet datatraffic channel (PDTCH), it is determined that the NE is in the Busystate, that is, the NE needs to output an RF signal.

After the state of the NE is obtained, the voltage signal is outputaccording to the state. When the system is in the Busy state, thevoltage signal corresponding to the Busy state is output; and when thesystem is in the Idle state, the voltage signal corresponding to theIdle state is output. The value of the voltage signal varies withdifferent power amplifier transistors. For example, if the poweramplifier transistor is an N-channel LDMOS, the voltage signalcorresponding to the Busy state may be 2 V to 5 V, and the voltagesignal corresponding to the Idle state may be 0 V to 2 V. Besides, ifthe power amplifier transistor is an N-channel depletion-mode galliumarsenide metal-semiconductor field effect transistor (GaAs MESFET), thevoltage signal corresponding to the Busy state may be −4 V to 0 V, andthe voltage signal corresponding to the Idle state may be −5 V to −4 V.

Step S102, applying the voltage signal to a grid electrode or a baseelectrode of at least one power amplifier transistor in a poweramplifier.

When the NE is in the Busy state, the voltage signal corresponding tothe Busy state is applied to the grid electrode or the base electrode ofone or more power amplifier transistors in the power amplifier. At thistime, the power amplifier transistor works in an amplification range,and the power amplifier has RF power output. When the NE is in the Idlestate, the voltage signal corresponding to the Idle state is applied tothe grid electrode or the base electrode of one or more power amplifiertransistors in the power amplifier. At this time, the power amplifiertransistor switches off with no RF power output, and thus does not havestatic power dissipation.

After the method of the present invention is described in the aboveembodiment, the difference between DC power dissipation of the poweramplifier in the method of the present invention and that of the poweramplifier in the prior art is given below with specific examples.

It is assumed that FIG. 2 is a schematic view of the relationshipbetween the RF power output of a Class A or Class AB power amplifier ineight timeslot periods and timeslots according to the first embodimentof the present invention, in which the Pf axis represents the RF outputpower, and the t axis represents the timeslots. The timeslots 2, 4, and6 are idle timeslots, during which the power amplifier does not have RFpower output; while the timeslots 1, 3, 5, 7, and 8 are non-idletimeslots, during which the power amplifier has RF power output.

FIG. 3 is a schematic view of the relationship between the powerdissipation of a conventional Class AB power amplifier in the prior artand the timeslots in the RF power output state as shown in FIG. 2. InFIG. 3, the Pq1 axis represents the power dissipation of the poweramplifier, the Vg1 axis represents a grid electrode bias voltage of thepower amplifier transistor in the power amplifier, and the dashed lineVgs1 represents a current grid bias voltage of the power amplifiertransistor. As shown in FIG. 3, Vgs1 is constant (normally between 2 Vand 5 V), and the power dissipation is not zero in the idle timeslots 2,4, and 6.

FIG. 4 is a schematic view of the relationship between the powerdissipation of the Class A or Class AB power amplifier utilizing themethod embodiment of the present invention and the timeslots in the RFpower output state as shown in FIG. 2. In FIG. 4, the Pq2 axisrepresents the power dissipation of the power amplifier, the Vg2 axisrepresents a grid electrode bias voltage of the power amplifiertransistor in the power amplifier, and the dashed line Vgs2 represents acurrent grid electrode bias voltage of the power amplifier transistor.As shown in FIG. 4, Vgs2 varies with the state of the timeslots. In theidle timeslots 2, 4, and 6, Vgs2 is between 0 V and 2 V, the poweramplifier transistor switches off, and the power dissipation of thepower amplifier is zero; while in the non-idle timeslots 1, 3, 5, 7, and8, Vgs2 is between 2 V and 5 V, the power amplifier transistor works inan amplification range, and the power amplifier has RF power output.

If the power amplifier transistor in the power amplifier is a bipolarjunction transistor (BJT), the efficiency of the power amplifier canstill be improved by using the above method, and the difference lies inthat Vgs2 represents a base bias voltage of the BJT, and the value ofVgs2 in the idle and non-idle timeslots can be adjusted according tospecific parameters of the transistor.

As described above, the voltage of the voltage signal (for example,Vgs2) is relatively low, so that the voltage control circuit does notneed high-capacitance capacitors or high-inductance inductors, and theresponse time can meet the requirements for the timeslot period of thesubscribers. By using the method embodiment of the present invention,the power dissipation of the power amplifier is much lower than that ofthe conventional Class AB power amplifier in the prior art, so as tosignificantly improve the efficiency of the power amplifier.

The method for controlling power amplification is applicable to an RFtransmitter, and is also applicable to an NE including, but not limitedto, a base station, a wireless terminal, a server, a switch, and a basestation controller.

A system for controlling power amplification is provided in a secondembodiment of the present invention. Referring to FIG. 5, the systemincludes a main control unit 200, a voltage control unit 210, and apower amplifier unit, in which the power amplifier unit includes a poweramplifier 220.

Referring to FIG. 6, the main control unit 200 is adapted to obtain thestate of an NE, and send a voltage control signal according to thestate.

The main control unit 200 includes an information acquisition module202, a state acquisition module 204, and a signal sending module 206.

The information acquisition module 202 is adapted to acquire informationrelated to the NE through a port A21. The information includes signalingor service information or external control signals or internal clocksignals of the NE. Priorities of the signals may be set in the maincontrol unit, for example, the priority of the external control signalsis set to the highest, and thus, when a fault alarm signal or a signalfor forcedly turning off the transmitter or power amplifier is received,even if the NE is in the non-idle timeslots as indicated by thesignaling, the main control unit still determines the state of the NE asIdle according to the priority.

The state acquisition module 204 is adapted to determine a current stateof the NE according to the above information. The NE may be in an Idlestate or a Busy state. The Idle state indicates that the NE is notrequired to output an RF signal, for example, the NE is not accessed byany subscriber, in an idle timeslot, or receives a control signal forenabling the power amplifier to switch off. The Busy state indicatesthat the NE is required to output an RF signal, for example, the NE isaccessed by subscribers, in a non-idle timeslot, or receives a controlsignal for turning on the power amplifier.

The signal sending module 206 is adapted to send the voltage signalaccording to the state of the NE. For example, the voltage controlsignal corresponding to the Idle state is represented by a logic voltage“0”, and the voltage control signal corresponding to the Busy state isrepresented by a logic voltage “1”. Further, an inverse logic expressionmay also be adopted, that is, the voltage control signal correspondingto the Idle state is represented by a logic voltage “1”, and the voltagecontrol signal corresponding to the Busy state is represented by a logicvoltage “0”. The voltage control signal is output from a port A22.

The main control unit 200 may be an integrated chip or a functionalmodule of an integrated chip, for example, a functional moduleintegrated in a control chip of a wireless terminal such as a mobilephone. The main control unit 200 may also be a part of a base stationcontroller, and the voltage control signal is directly sent to atransmitter on a base station side through a signaling channel by thebase station controller. The main control unit 200 may also be directlyintegrated on a board of a transmitter.

The voltage control unit 210 is connected to the main control unit 200,and adapted to receive the voltage control signal from the main controlunit 200 through a port B21, obtain the voltage signal according to thevoltage control signal, and apply the obtained voltage signal to a gridelectrode or a base electrode of a power amplifier transistor 221 in thepower amplifier 220 through a port B22. The value of the voltage signalvaries for different power amplifier transistors. For example, when thepower amplifier transistor is an N-channel LDMOS, the voltage signalcorresponding to the voltage control signal “1” (the Busy state) may be2 V to 5 V, and the voltage signal corresponding to the voltage controlsignal “0” (the Idle state) may be 0 V to 2 V. When the power amplifiertransistor is an N-channel depletion-mode GaAs MESFET, the voltagesignal corresponding to the voltage control signal “1” (the Busy state)may be −4 V to 0 V, and the voltage signal corresponding to the voltagecontrol signal “0” (the Idle state) may be −5 V to −4 V. The voltagecontrol unit may be formed by an analog switch circuit or adigital-to-analog converter circuit. The voltage control unit may be setseparately or integrated in the main control unit as a functionalmodule.

The power amplifier 220 is adapted to switch on or switch off accordingto the bias voltage signal applied to the grid electrode or a baseelectrode of the power amplifier transistor 221 therein. A port C21 ofthe power amplifier 220 is adapted to receive an RF signal, a port C22is adapted to connect a constant power supply voltage V_(dd), and a portC23 is adapted to output the RF signal.

The power amplifier 220 may be a Class A or Class AB amplifier, and thepower amplifier transistor 221 therein includes, but is not limited to,an LDMOS, a GaAs MESFET, a BJT, a junction field effect transistor(JFET), or a gallium nitride (GAN) transistor.

When the power amplifier is formed by multiple power amplifiertransistors, the voltage control unit enables the power amplifier toswitch on or switch off by controlling the grid voltage or base voltageof the one or multiple power amplifier transistors in the poweramplifier. As shown in FIG. 7, a main control unit 300 obtainsinformation related to an NE through a port A31, a port A32 sends avoltage control signal to a port B31 of a voltage control unit 310, thevoltage control unit 310 responds to the signal, and a port B32 outputsa voltage signal to a grid electrode or a base electrode of a poweramplifier transistor 321 and a grid electrode or a base electrode of apower amplifier transistor 322 in a power amplifier 320. A port C31 ofthe power amplifier 320 is adapted to receive an RF signal, a port C32is adapted to connect a constant power supply voltage V_(dd), and a portC33 is adapted to output the RF signal. In practice, the power amplifiertransistors connected to and controlled by the voltage control unit maybe determined according to the internal structure of the poweramplifier. When multiple power amplifier transistors need to becontrolled, multiple voltage signals are used, which vary according tospecific conditions of the power amplifier.

As the voltage control unit processes low-voltage and low-currentsignals, the circuit structure is simple, and the manufacturing cost islow. Moreover, as the circuit includes fewer components, the stabilityof the circuit is also improved.

The system for controlling power amplification is applicable to an RFtransmitter, and is also applicable to an NE such as a base station or awireless terminal. When the system for controlling power amplificationis applied in the wireless terminal, in order to simplify the equipmentconnection and improve the integration level, the voltage control unitmay be directly integrated in the main control unit, or the main controlunit, the voltage control unit, and the power amplifier unit may beintegrated in a chip or in a functional module of a chip.

A system for controlling power amplification is provided in a thirdembodiment of the present invention, in which a voltage control unit isintegrated in a main control unit. Referring to FIG. 8, the systemincludes a main control unit 400 and a power amplifier unit, and thepower amplifier unit includes a power amplifier 420.

A voltage control unit 401 is integrated in the main control unit 400. Aport A41 of the main control unit 400 is an information input portadapted to obtain information related to an NE. The information includesat least one of signaling, service information, external controlsignals, and internal clock signals of the NE. A current state of the NEis determined according to the above information. A bias voltage signalis applied to a grid electrode or a base electrode of a power amplifiertransistor 421 according to the current state of the NE.

The NE may be in an Idle state or a Busy state. The Idle state indicatesthat the NE is not required to output an RF signal, for example, the NEis not accessed by any subscriber, in an Idle timeslot, or receives acontrol signal for turning off the power amplifier. The Busy stateindicates that the NE is required to output an RF signal, for example,the NE is accessed by subscribers, in a non-idle timeslot, or receives acontrol signal for turning on the power amplifier. Taking a GSM mobileterminal for example, in the process that the terminal establishesconnections, the network side delivers a service channel assignmentmessage, in which sequence numbers of timeslots available to theterminal are specified. The main control unit obtains the message, anddetermines whether the terminal is in a Busy state according to themessage and the internal clock when the specified timeslots arrive.

The voltage control unit 401 integrated in the main control unit 400outputs a voltage signal according to the state of the NE, and thevoltage signal is applied to the grid electrode or the base electrode ofthe power amplifier transistor 421 through a port A42. The value of thevoltage signal varies for different power amplifier transistors. Forexample, if the power amplifier transistor is an N-channel LDMOS, thevoltage signal corresponding to the Busy state of the NE may be 2 V to 5V, and the voltage signal corresponding to the Idle state may be 0 V to2 V. If the power amplifier transistor is an N-channel depletion-modeGaAs MESFET, the voltage signal corresponding to the Busy state may be−4 V to 0 V, and the voltage signal corresponding to the Idle state maybe −5 V to −4 V.

The power amplifier 420 is adapted to switch on or switch off accordingto the voltage signal applied to the grid electrode or the baseelectrode of the power amplifier transistor 421 therein. A port C41 ofthe power amplifier 420 is adapted to receive an RF signal, a port C42is adapted to connect a constant power supply voltage V_(dd), and a portC43 is adapted to output the RF signal.

The power amplifier 420 may be a Class A or Class AB amplifier, and thepower amplifier transistor 421 therein includes, but is not limited to,an LDMOS, a GaAs MESFET, a BJT, a JFET, or a GAN transistor.

The voltage control unit is directly integrated in the main controlunit. Thus, the integration level of the equipment is improved, theconfiguration and circuit connection are simplified, and the delay ofthe control signal is significantly shortened to make the response tothe voltage signal more timely. In addition, the function of the maincontrol unit 400 may be realized through a dedicated integrated circuit,a central processing unit (CPU), or a field programmable gate array(FPGA).

The system for controlling power amplification is applicable to an RFtransmitter, and is also applicable to an NE such as a base station or awireless terminal.

According to actual requirements, the voltage control unit may also bedirectly integrated in the power amplifier.

A system for controlling power amplification is provided in a fourthembodiment of the present invention, in which a voltage control unit isintegrated in a power amplifier. Referring to FIG. 9, the systemincludes a main control unit 500 and a power amplifier 520.

A port A51 of the main control unit 500 is an information input portadapted to obtain information related to an NE. The information includesat least one of signaling, service information, external controlsignals, and internal clock signals of the NE. A current state of the NEis determined according to the above information.

The NE may be in an Idle state or a Busy state. The Idle state indicatesthat the NE is not required to output an RF signal, for example, the NEis not accessed by any subscriber, in an idle timeslot, or receives acontrol signal for turning off the power amplifier. The Busy stateindicates that the NE is required to output an RF signal, for example,the NE is accessed by subscribers, in a non-idle timeslot, or receives acontrol signal for turning on the power amplifier.

The main control unit 500 sends a voltage control signal according tothe state of the NE. For example, the voltage control signalcorresponding to the Idle state is represented by a logic voltage “0”,and the voltage control signal corresponding to the Busy state isrepresented by a logic voltage “1”. Further, an inverse logic expressionmay also be adopted, that is, the voltage control signal correspondingto the Idle state is represented by a logic voltage “1”, and the voltagecontrol signal corresponding to the Busy state is represented by a logicvoltage “0”. The voltage control signal is output from a port A52. Themain control unit 500 may be an integrated chip or a functional moduleof an integrated chip. The main control unit may also be a part of abase station controller, and the voltage control signal is directly sentto a transmitter on a base station side through a signaling channel bythe base station controller. The main control unit may also beintegrated in a baseband signal processing subsystem of a base station,or directly integrated on a board of a transmitter.

A voltage control unit 522 is integrated in the power amplifier 520. Aport C54 of the voltage control unit 522 receives the voltage controlsignal from the main control unit 500. The voltage control unit 522responds to the voltage control signal, and applies a voltage signal toa grid electrode or a base electrode of a power amplifier transistor521. The power amplifier transistor switches on or switches offaccording to the voltage signal. The value of the voltage signal variesfor different power amplifier transistors. For example, when the poweramplifier transistor is an N-channel LDMOS, the voltage signalcorresponding to the voltage control signal “1” (the Busy state) may be2 V to 5 V, and the voltage signal corresponding to the voltage controlsignal “0” (the Idle state) may be 0 V to 2 V. If the power amplifiertransistor is an N-channel depletion-mode GaAs MESFET, the voltagesignal corresponding to the voltage control signal “1” (the Busy state)may be −4 V to 0 V, and the voltage signal corresponding to the voltagecontrol signal “0” (the Idle state) may be −5 V to −4 V. A port C51 ofthe power amplifier 520 is adapted to receive an RF signal, a port C52is adapted to connect a constant voltage V_(dd) of power source, and aport C53 is adapted to output the RF signal.

The power amplifier 520 may be a Class A or Class AB amplifier, and thepower amplifier transistor 521 therein includes, but is not limited to,an LDMOS, a GaAs MESFET, a BJT, a JFET, or a GAN transistor. The poweramplifier 520 may also be an integrated circuit, and the voltage controlunit therein is implemented through a digital-to-analog convertercircuit or an analog switch circuit.

The voltage control unit is integrated in the power amplifier unit(which includes the power amplifier). Thus, the universality of thepower amplifier unit is improved. Moreover, as the transmission path ofthe voltage signal is short, the interference to the voltage signalcaused by other signals is effectively prevented. Therefore, thisconfiguration is applicable when the main control unit is at a longdistance to the power amplifier.

The system for controlling power amplification is applicable to an RFtransmitter, and is also applicable to an NE such as a base station or awireless terminal.

A system for controlling power amplification is provided in a fifthembodiment of the present invention, in which multiple power amplifiersare operated independently or connected in parallel in operation.Referring to FIG. 10, the system includes a main control unit 600, avoltage control unit 610, and a power amplifier unit formed by a firstpower amplifier 620, a second power amplifier 630, and a third poweramplifier 640.

A port A61 of the main control unit 600 is an information input portadapted to obtain information related to an NE. The information includesat least one of signaling, service information, external controlsignals, and internal clock signals of the NE. A current state of the NEis determined according to the above information.

The NE may be in an Idle state or a Busy state. The Idle state indicatesthat the NE is not required to output an RF signal, for example, the NEis not accessed by any subscriber, in an idle timeslot, or receives acontrol signal for turning off the power amplifier. The Busy stateindicates that the NE is required to output an RF signal, for example,the NE is accessed by subscribers, in a non-idle timeslot, or receives acontrol signal for turning on the power amplifier.

The main control unit 600 sends a voltage control signal according tothe state of the NE. For example, the voltage control signalcorresponding to the Idle state is represented by a logic voltage “0”,and the voltage control signal corresponding to the Busy state isrepresented by a logic voltage “1”. Further, an inverse logic expressionmay also be adopted, that is, the voltage control signal correspondingto the Idle state is represented by a logic voltage “1”, and the voltagecontrol signal corresponding to the Busy state is represented by a logicvoltage “0”. The voltage control signal is output from a port A62. Whenthe power amplifier unit is formed by multiple power amplifiers, themain control unit outputs multiple independent voltage control signals,and the logic expression of each voltage control signal is the same asthe preceding description. The main control unit 600 may be anintegrated chip or a functional module of an integrated chip. The maincontrol unit may also be a part of a base station controller, and thevoltage control signal is directly sent to a transmitter on a basestation side through a signaling channel by the base station controller.The main control unit may also be directly integrated on a board of atransmitter.

The voltage control unit 610 is connected to the main control unit 600,and adapted to receive the voltage control signals from the main controlunit 600 through a port B61, obtain voltage signals according to thevoltage control signals, and apply the obtained voltage signals to gridelectrodes of the power amplifier transistors 621, 631, and 641 or baseelectrodes of the power amplifier transistors 621, 631, and 641 througha port B62, respectively. Here, the port B62 can output threeindependent voltage signals to control the three power amplifiersindependently, or output only one voltage signal to control the threepower amplifiers uniformly. The value of the voltage signals varies fordifferent power amplifier transistors. For example, when the poweramplifier transistors are N-channel LDMOSs, the voltage signalscorresponding to the voltage control signals “1” (the Busy state) may be2 V to 5 V, and the voltage signals corresponding to the voltage controlsignals “0” (the Idle state) may be 0 V to 2 V. If the power amplifiertransistors are N-channel depletion-mode GaAs MESFETs, the voltagesignals corresponding to the voltage control signals “1” (the Busystate) may be −4 V to 0 V, and the voltage signals corresponding to thevoltage control signals “0” (the Idle state) may be −5 V to −4 V. Thevoltage control unit may be formed by an analog switch circuit or adigital-to-analog converter circuit. The voltage control unit may be setseparately or integrated in the main control unit or the power amplifierunit as a functional module.

When the first power amplifier 620, the second power amplifier 630, andthe third power amplifier 640 operate independently, ports C61, C64, andC67 receive three independent RF signals, and ports C63, C66, and C69output three amplified RF signals, respectively. Each of the poweramplifiers is adapted to switch on or switch off according to thevoltage signal applied to the grid electrode or the base electrode ofthe power amplifier transistor therein. The first power amplifier 620,the second power amplifier 630, and the third power amplifier 640 mayrespectively include one or more power amplifier transistors, and portsC62, C65, and C68 thereof are connected to a constant power supplyvoltage V_(dd) respectively.

When the power amplifiers operate in parallel, the ports C61, C64, andC67 receive one RF signal, which is then divided into three signals. Thethree signals are amplified by the three power amplifiers, then combinedby the ports C63, C66, and C69, and output as one RF signal. Each of thepower amplifiers is adapted to switch on or switch off according to abias voltage signal applied to the grid electrode or the base electrodeof the power amplifier transistor therein. The first power amplifier620, the second power amplifier 630, and the third power amplifier 640may respectively include one or more power amplifier transistors, andthe ports C62, C65, and C68 thereof are connected to a constant voltageV_(dd) of a power source respectively. The main control unit controls,via the voltage signal, the number of the power amplifiers which are inthe On state, according to the input RF power, so as to improve theoverall efficiency of the power amplifier unit. For example, only onepower amplifier switches on when the power of the input RF signal issmall, and three power amplifiers are turned on when the power of theinput RF signal is large. The three power amplifiers may be controlleduniformly by one voltage signal, so as to double the output power.

The first power amplifier 620, the second power amplifier 630, and thethird power amplifier 640 may be Class A or Class AB amplifiers, and thepower amplifier transistors therein include, but are not limited to,LDMOS, GaAs MESFET, BJT, JFET, or GAN transistors.

The main control unit outputs multiple voltage signals through thevoltage control unit, which realizes the collective control overmultiple power amplifiers, saves the equipment cost, and improves theefficiency of the power amplifiers.

The system for controlling power amplification is applicable to an RFtransmitter, and is also applicable to an NE such as a base station or awireless terminal.

Sometimes, multiple power amplifiers need to be connected in series inoperation to obtain a higher gain. A system for controlling poweramplification is provided in a sixth embodiment of the presentinvention, in which power amplifiers are connected in series inoperation. Referring to FIG. 11, the system includes a main control unit700, a voltage control unit 710, and a power amplifier unit formed by afirst power amplifier 720, a second power amplifier 730, and a thirdpower amplifier 740.

A port A71 of the main control unit 700 is an information input portadapted to obtain information related to an NE. The information includesat least one of signaling, service information, external controlsignals, and internal clock signals of the NE. A current state of the NEis determined according to the above information.

The NE may be in an Idle state or a Busy state. The Idle state indicatesthat the NE is not required to output an RF signal, for example, the NEis not accessed by any subscriber, in an idle timeslot, or receives acontrol signal for turning off the power amplifier. The Busy stateindicates that the NE is required to output an RF signal, for example,the NE is accessed by subscribers, in a non-idle timeslot, or receives acontrol signal for turning on the power amplifier.

The main control unit 700 sends a voltage control signal according tothe state of the NE. For example, the voltage control signalcorresponding to the Idle state is represented by a logic voltage “0”,and the voltage control signal corresponding to the Busy state isrepresented by a logic voltage “1”. Further, an inverse logic expressionmay also be adopted, that is, the voltage control signal correspondingto the Idle state is represented by a logic voltage “1”, and the voltagecontrol signal corresponding to the Busy state is represented by a logicvoltage “0”. The voltage control signal is output from a port A72. Ifthe power amplifier unit is formed by multiple power amplifiers, themain control unit outputs multiple independent voltage control signals,and the logic expression of each voltage control signal is the same asthe preceding description. The main control unit 700 may be anintegrated chip or a functional module of an integrated chip. The maincontrol unit may also be a part of a base station controller, and thevoltage control signal is directly sent to a transmitter on a basestation side through a signaling channel by the base station controller.The main control unit may also be directly integrated on a board of atransmitter.

The voltage control unit 710 is connected to the main control unit 700,and adapted to receive the voltage control signals from the main controlunit 700 through a port B71, obtain voltage signals according to thevoltage control signals, and apply the obtained voltage signals to gridelectrodes of the power amplifier transistors 721, 731, and 741 or baseelectrodes of the power amplifier transistors 721, 731, and 741 througha port B72, respectively. Here, the port B72 can output threeindependent voltage signals to control the three power amplifiersindependently, or output only one voltage signal to control the threepower amplifiers uniformly. In addition, for the power amplifiersconnected in series, the voltage signal may be applied to individualpower amplifiers. For example, in this embodiment, the voltage signal isapplied to only the grid electrode of the power amplifier transistor 741in the last power amplifier 740. The value of the voltage signal variesfor different power amplifier transistors. For example, If the poweramplifier transistors are N-channel LDMOSs, the voltage signalscorresponding to the voltage control signals “1” (the Busy state) may be2 V to 5 V, and the voltage signals corresponding to the voltage controlsignals “0” (the Idle state) may be 0 V to 2 V. When the power amplifiertransistors are N-channel depletion-mode GaAs MESFETs, the voltagesignals corresponding to the voltage control signals “1” (the Busystate) may be −4 V to 0 V, and the voltage signals corresponding to thevoltage control signals “0” (the Idle state) may be −5 V to −4 V. Thevoltage control unit may be formed by an analog switch circuit or adigital-to-analog converter circuit. The voltage control unit may be setseparately or integrated in the main control unit or the power amplifierunit as a functional module.

The first power amplifier 720, the second power amplifier 730, and thethird power amplifier 740 are connected in series in operation, and eachof the power amplifiers switch on or switch off according to a biasvoltage signal applied to the grid electrode or the base electrode ofthe power amplifier transistor therein. The first power amplifier 720,the second power amplifier 730, and the third power amplifier 740 mayrespectively include one or more power amplifier transistors. A port C71is an RF signal input terminal, ports C73 and C74 are connected, portsC76 and C77 are connected such that the RF signals are amplified onthree stages and output from a port C79, and ports C72, C75, and C78 areconnected to a constant voltage V_(dd) of a power supply respectively.

The first power amplifier 720, the second power amplifier 730, and thethird power amplifier 740 may be Class A or Class AB amplifiers, and thepower amplifier transistors therein include, but are not limited to,LDMOS, GaAs MESFET, BJT, JFET, or GAN transistors.

The system for controlling power amplification is applicable to an RFtransmitter, and is also applicable to an NE such as a base station or awireless terminal.

A device for controlling power amplification is provided in a seventhembodiment of the present invention. The device includes a main controlunit and a voltage control unit. The main control unit is adapted toobtain the state of an NE, and send a voltage control signal accordingto the state. The voltage control unit is adapted to output a voltagesignal to a grid electrode or a base electrode of a power amplifiertransistor in a power amplifier unit according to the voltage controlsignal.

The main control unit further includes an information acquisitionmodule, a state acquisition module, and a signal sending module.

The information acquisition module is adapted to acquire informationrelated to the equipment. The information is signaling, serviceinformation, control signals, or internal clock signals.

The state acquisition module is adapted to acquire the state of theequipment according to the above information.

The signal sending module is adapted to send the voltage signalaccording to the state of the equipment.

Though several specific embodiments of the present invention aredisclosed above, the present invention is not limited thereto. Variousmodifications and variations that can be thought of by persons skilledin the art shall fall within the protective scope of the presentinvention.

What is claimed is:
 1. A method for controlling power amplification, themethod comprising: determining whether a network equipment is in an idlestate or in a busy state, wherein the idle state indicates that thenetwork equipment is in an idle timeslot, and not accessed by anysubscriber; and when the network equipment is in the idle state,outputting a first voltage signal to a grid electrode or a baseelectrode of at least one power amplifier transistor in a poweramplifier in order to enable the power amplifier transistor to switchoff according to the first voltage signal.
 2. The method of claim 1,further comprising when the network equipment is in the busy state,outputting a second voltage signal to the grid electrode or the baseelectrode of the at least one power amplifier transistor in the poweramplifier in order to enable the power amplifier transistor to switch onaccording to the second voltage signal.
 3. The method of claim 1,wherein determining whether the network equipment is in the idle stateor in the busy state comprises determining according to informationrelated to the network equipment.
 4. The method of claim 3, wherein theinformation related to the network equipment comprises at least one of asignaling, service information, an external control signal and aninternal clock signal of the network equipment.
 5. The method of claim1, wherein the network equipment comprises a base station.
 6. The methodof claim 1, wherein the busy state indicates that the network equipmentis required to output an RF signal in a time slot.
 7. A poweramplification controller used in a network equipment, wherein the poweramplification controller is configured to determine whether the networkequipment is in an idle state or in a busy state and when the networkequipment is in the idle state, output a first voltage signal to a gridelectrode or a base electrode of at least one power amplifier transistorin a power amplifier in order to enable the power amplifier transistorto switch off according to the first voltage signal, wherein the idlestate indicates that the network equipment is in an idle timeslot, andnot accessed by any subscriber.
 8. The power amplification controller ofclaim 7, wherein, when the network equipment is in the busy state, thepower amplification controller is further configured to output a secondvoltage signal to the grid electrode or the base electrode of the atleast one power amplifier transistor in the power amplifier in order toenable the power amplifier transistor to switch on according to thesecond voltage signal.
 9. The power amplification controller of claim 7,wherein the power amplification controller is further configured todetermine whether the network equipment is in the idle state or in thebusy state according to information related to the network equipment.10. The power amplification controller of claim 9, wherein theinformation related to the network equipment comprises at least one of asignaling, service information, an external control signal and aninternal clock signal of the network equipment.
 11. The poweramplification controller of claim 7, wherein the network equipmentcomprises a base station.
 12. The power amplification controller ofclaim 7, wherein the busy state indicates that the network equipment isrequired to output an RF signal in a time slot.
 13. A network equipmentcomprising a power amplification controller and a power amplifier,wherein the power amplification controller is configured to determinewhether the network equipment is in an idle state or in a busy stateand, when the network equipment is in the idle state, to output a firstvoltage signal to a grid electrode or a base electrode of a poweramplifier transistor in the power amplifier in order to enable the poweramplifier transistor to switch off according to the first voltagesignal, wherein the idle state indicates that the network equipment isin an idle timeslot, and not accessed by any subscriber.
 14. The networkequipment according to claim 13, wherein, when the network equipment isin the busy state, the power amplification controller is furtherconfigured to output a second voltage signal to the grid electrode orthe base electrode of the power amplifier transistor in the poweramplifier in order to enable the power amplifier transistor to switch onaccording to the second voltage signal.
 15. The network equipment ofclaim 13, wherein the power amplification controller is furtherconfigured to determine whether the network equipment is in the idlestate or in the busy state according to information related to thenetwork equipment.
 16. The network equipment of claim 15, wherein theinformation related to the network equipment comprises at least one of asignaling, service information, an external control signal and aninternal clock signal of the network equipment.
 17. The networkequipment of claim 13, wherein the network equipment comprises a basestation.
 18. The network equipment according to claim 13, wherein thebusy state indicates that the network equipment is required to output anRF signal in a time slot.